No, all that the researchers have done is show a change.
They haven't shown that the change was EITHER natural or manmade.
Thus, the entire premise of the article is unfounded.
Posted on 01/06/2003 10:48:27 AM PST by cogitator
Scientists discover global warming linked to increase in tropopause height over past two decades
LIVERMORE, Calif. -- Researchers at the Lawrence Livermore National Laboratory have discovered another fingerprint of human effects on global climate.
Recent research has shown that increases in the height of the tropopause over the past two decades are directly linked to ozone depletion and increased greenhouse gases.
The tropopause is the transition zone between the lowest layer of the atmosphere -- the turbulently-mixed troposphere -- and the more stable stratosphere. The tropopause lies roughly 10 miles above the Earth's surface at the equator and five miles above the poles. To date, no scientist has examined whether observed changes in tropopause height are in accord with projections from climate model greenhouse warming experiments.
The comparison was made by Livermore scientists Benjamin Santer, James Boyle, Krishna AchutaRao, Charles Doutriaux and Karl Taylor, along with researchers from the National Center for Atmospheric Research, NASA Goddard Institute for Space Studies, the Max-Planck Institute for Meteorology and the Institut for Physik der Atmosphere in Germany. Their findings are reported in the today's (Jan. 3) online edition of the Journal of Geophysical Research-Atmospheres.
This research undercuts claims by greenhouse skeptics that no warming has occurred during the last two decades. Such claims are based on satellite measurements of temperatures in the troposphere, which show little or no warming since the beginning of the satellite record in 1979.
"Weather balloons and weather forecast models show that there's been a pronounced increase in the height of the global tropopause over the last two decades," Santer said. "Our best understanding is that this increase is due to two factors: warming of troposphere, which is caused by increasing greenhouse gases, and cooling of the stratosphere, which is mainly caused by depletion of stratospheric ozone. Tropopause height changes give us independent evidence of the reality of recent warming of the troposphere."
The Livermore research supports the bottom-line conclusion of the 2001 Intergovernmental Panel on Climate Change (IPCC), which states that, "most of the observed warming over the last 50 years is likely to have been due to the increase in greenhouse gas concentrations."
Earlier research showed that changes in the Earth's surface temperature, ocean heat content, and Northern Hemisphere sea ice cover are other indicators of human effects on climate change.
"The climate system is telling us a consistent story -- that humans have had a significant effect on it," Santer said. "We're seeing detailed correspondence between computer climate models and observations, and this correspondence is in a number of different climate variables. Tropopause height is the latest piece of the climate-change puzzle."
To support the research, Livermore scientists examined tropopause height changes in climate-change experiments using two different computer climate models. Both models showed similar decadal-scale increases in the tropopause height in response to changes in human-caused climate forcings. The patterns of tropopause height change were similar in models and so-called 'reanalysis' products (a combination of actual observations and results from a weather forecast model).
The model experiments focused on both manmade climate forcings, such as changes in well-mixed greenhouse gases, stratospheric and tropospheric ozone, and on natural forcings, such as changes in volcanic aerosols. The forces have varying effects on atmospheric temperature, that in turn affect tropopause height, the report concludes.
Founded in 1952, Lawrence Livermore National Laboratory is a national security laboratory, with a mission to ensure national security and apply science and technology to the important issues of our time. Lawrence Livermore National Laboratory is managed by the University of California for the U.S. Department of Energy's National Nuclear Security Administration.
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Try selling "Global Warming" worries to folks in Northern Ohio!
This research undercuts claims by greenhouse skeptics that no warming has occurred during the last two decades. Such claims are based on satellite measurements of temperatures in the troposphere, which show little or no warming since the beginning of the satellite record in 1979.
I can only think that if the troposphere is thicker (and therefore has more mass?), and its average temperature is unchanged, then its total heat content must have increased.
My wife has this.
But, so what? The box just got bigger. This doesn't show that the rate of heat input increased.
Now if the altitude of the Tropopause has increased, does that not imply lower average temperatures below the Tropopause?
This research undercuts claims by greenhouse skeptics that no warming has occurred during the last two decades. Such claims are based on satellite measurements of temperatures in the troposphere, which show little or no warming since the beginning of the satellite record in 1979.
"Weather balloons and weather forecast models show that there's been a pronounced increase in the height of the global tropopause over the last two decades," Santer said. "Our best understanding is that this increase is due to two factors: warming of troposphere, which is caused by increasing greenhouse gases, ...
Now if the altitude of the Tropopause has increased, does that not imply lower average temperatures below the Tropopause?
Ouch. That makes my head hurt trying to figure this mess out. Why can't we just say, "changes in the earth's climate are likely caused by the sun," and leave it at that?
No, all that the researchers have done is show a change.
They haven't shown that the change was EITHER natural or manmade.
Thus, the entire premise of the article is unfounded.
It was 0.6 C over the whole 20th Century. In the past 25 years or so, global temperatures have increased about 0.4 C, (or 1.8 C century). Those two observations aren't in conflict because there was a slight drop in global temperatures from the 1940s to the 1970s.
I think it implies that temperatures below the tropopause have increased.
Sorry to hear that. She must be an airhead.
Global cooling may be harmful to your health if you are homeless or impoverished. Freezing temperatures have been known to cause physical injury and death, especially among disadvantaged people.
If you learn that your frostbite is due to cooling actions instigated by environmentalists, consult your local lawyer. He or she can advise you of your chances of winning a lawsuit against the "Gotta be cool" crowd.
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